question

I hate to be the bearer of bad news, but the ESS Assistant module is not intended to be used in this manor, nor do I think there is any way of accomplishing this except by manually disconnecting the AC-Input using some sort of relay switch. The ESS manual in fact specifically says not to use it for this:

When not to use ESS

• Off-grid systems - either with or without generator.

• Marine systems.

• Automotive systems.

• Inverter priority, also known as 'Intentional islanding“ or 'Ignore AC' input systems.

By default, and unless there is some trick I am not aware of, when running ESS you are always "on-grid" as long as the AC-Input remains active. This is just a fact of how this feature works.

If you have your grid set-point at 0W though, and sufficient PV, battery and inverter power, then there is no reason that 99% of your AC consumption should not be coming from Off-Grid. You should be able to see in the VRM portal depending on how the system was setup, exactly how much is being taken from the grid throughout the day.

Hi @DanievS

This is probably done in the inverter, using an assistant.

Why Exactly this cannot be changed with your batteries I don't know.

@DanievS I would be interested to know what settings you have. My MP II with 8.8 LG Resu typically "disconnects" grid when it reaches the min SOC plus 5%. Also, the reverse is true in that the battery is only charged from grid if it falls below the SOC to maintain min SOC. The MP II connected parallel to the grid with nothing wired on AC1 OUT. During the day it will charge battery using PV only until it reaches the min SOC + approx 5%, while grid services house. Once this level is reached, the PV serves house and continuous to charge battery with grid reduced to zero. What is your sustain voltage?

Thank you for all the advice and suggestions, appreciated.

To clarify some of the points mentioned:

1. SuperCap batt is only charged from PV's and not Grid. This is how I want it to be. When batt is at remaining power of 5%, the system switches to Grid - this typically only occurs at night.

2. During the day I have ample spare PV capacity to more than fully charge the batt.

The issue is that in the morning when the PV's starts to provide power, I could be off the Grid sooner, instead of the system remaining on Grid until the batt is just about fully charged.

The household power demand must get priority over the charging of the batt when there is sufficient PV power available to run household demand. Thereafter, once there is excess PV power, only then should it be utilised to charge the battery.

I am also of the opinion that there should be such a setting on the inverter - just a case of where. Victron is after all the best!!

Hi,

I saw another post the other day that was indicating it might be possible to use the Generator Flag to ignore the AC input. I'm not sure however if one can run this and ESS at the same time. I've not tried it but it might be worth looking in to? Here's the link https://www.victronenergy.com/live/assistants:ignore_ac_input_using_the_generator_assistant

Hello, try to use the K1 or K2 relay. Program it to close/open when the state of charge is at the value you are looking for. Than connect external relay switch (the voltages and Amps depends on the used inverter) and use it to connect/disconnect the grid. Is it clear?

You will newd just one more relay and thats it.

Just an interested observer here, but I think your main requirement from above is to not export your excess pv to the grid, rather self consume, even to the extent of having low Soc in the evenings.

Can't you just set for zero export? You will I think need a grid meter to allow that..